Gravel Calculator — Volume, Weight & Cost

Turn bed measurements into loose supply volume, bag counts or a bulk order. Keep density, compaction and purchasing assumptions visible.

Updated 5 November 2026·How we calculate

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Your gravel areas

Measure the finished bed

V = area × depth

Rectangle: L × W × D. Circle: π × (d ÷ 2)² × D. Specify whether your measured depth is loose or compacted.

Editable slab-base example: 12 × 10 ft, 4 in depth. These are example measurements, not a base-design recommendation.

Volume & material assumptions

Measured bed condition

Loose volume per 1 unit compacted volume

Example 1.20 means buy 1.20 m³ loose for 1.00 m³ compacted, before waste. This is an editable assumption; confirm with your supplier.

Additional waste allowance (%)Loose bulk density reference

Density valueDensity unit

Material / supplier labelDensity source / supplier note

Reference densities are indicative, not universal. Use loose supply density for the exact grading and moisture condition. Compacted density must not be entered here.

Bag product & local prices

Bag product label

Package sizePackage unit

Bag source / supplier note

Mass-based bags use the entered loose density. Volume-based bags use the stated loose capacity. Confirm the package with your supplier.

CurrencyPrice per selected bag

Bulk unitPrice per bulk unit

Supplier order increment (in selected bulk unit)

0 means no supplier rounding. Enter 0.5 for half-unit orders, for example. Extra delivery, minimum orders, labour, equipment, fees and tax are excluded.

Keep your estimates together

My project & shopping list …

Stored on this device only. Anyone with a shared link can read its estimates. Don’t put addresses or personal details in labels. Concrete, concrete bags, gravel and blockwork share this list. Compatible demand is combined before purchasing rounding. Up to 20 items; long projects may need printing instead of sharing.

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Storage, sharing & privacy

No dimension inputs or project payloads are sent to analytics. This preview has no ads, analytics or account system. Shared estimates are encoded in the URL fragment, not the page path. Projects are stored in this browser’s local database. Browser clearing, eviction or device loss can remove them; keep a shared link or printed copy of important estimates. Clear project removes database estimates; retained older storage may still appear for explicit recovery.

Incoming shared projects open for review. They never replace a saved project automatically. Save an individual shared estimate to add it to your local project.

Trace every quantity

From bed size to a supplier order

Volume, compaction, then waste

Net volume is the measured bed geometry. If it represents the finished compacted bed, multiply by your stated loose-per-compacted ratio. Apply waste once to that loose volume. Multiply loose supply volume by loose bulk density to estimate mass.

Supply = net × multiplier × (1 + waste ÷ 100)

Independent worked example

A 2 × 3 m bed at 0.1 m depth has 0.6 m³ net volume. At a user-specified multiplier of 1.2 and 10% waste: 0.6 × 1.2 × 1.1 = 0.792 m³ loose supply. At a user-entered density of 1,600 kg/m³ this is 1,267.2 kg, or 51 whole 25 kg bags.

One metric tonne is 1,000 kg. One US short ton is 2,000 lb (907.18474 kg). These units are not interchangeable.

Practical limits and ordering guidance

Density presets are starting estimates. Confirm the loose density with your supplier: material, grading and moisture affect weight. The compaction multiplier is a separate assumption that you should confirm for your project.

The default 25 kg bag is an editable example. Enter your supplier’s actual bag size, price and ordering increment. Combined shopping lists merge only compatible material and purchasing assumptions.

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